Ferroelectric and Displacement Properties of Lead Zirconate Titanate Thick Films Prepared by Chemical Solution Depositio
- PDF / 1,472,837 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 13 Downloads / 223 Views
Ferroelectric and Displacement Properties of Lead Zirconate Titanate Thick Films Prepared by Chemical Solution Deposition Process Takashi Iijima, Yoshinori Hayashi1 and Jun Onagawa1 Smart Structure Research Center, AIST, Tsukuba central 2, 1-1-1 Umezono, Tsukuba 305-8568, Japan 1 Faculty of Engineering, Tohoku Gakuin Univercity, 1-13-1 Chuo, Tagajo 985-8537, Japan
ABSTRACT
Crack free 10-µm-thick Pb1.1(Zr0.53Ti0.47)O3 (PZT) films were successfully fabricated using a chemical solution deposition process, and the ferroelectric and displacement properties were evaluated. A 0.5 M PZT precursor solution was prepared from trihydrated lead acetate, titanium iso-propoxide , zirconium n-propoxide, and 2-methoxyethanol as the solvent. The process of spin coating and pyrolysis at 500 oC was repeated five times, and then the precursor films were fired at 700 oC for 5 min. This sequence was repeated 30 times. Finally, the films were fired at 700 oC for 10 min. The fabricated crack-free PZT thick films showed (100) preferred orientation. A flat surface and dense microstructure was observed. The electrical properties were comparable with the bulk PZT ceramics. The dielectric constant and dissipation factor were εr = 1453 and tanδ = 0.039, and the remnant polarization and coercive field were Pr = 25 µC/cm2 and Ec = 30 kV/cm, respectively. Field-induced displacement of the films was measured using an atomic force microscope (AFM) with and without a top electrode using a contact mode.
INTRODUCTION
Lead zirconate titanate (PZT) films are in demand for applications in many fields like memories, sensors and actuators. Combining the preparation technique for ferroelectric films with a Si micro-machining process is an effective way to fabricate microelectromechanical systems (MEMS), such as piezoelectric micro-actuator devices for applications in the electrical and medical fields [1, 2]. However, the amount of the displacement and force of PZT films is not sufficient in some microactuator applications, so that various processes were investigated to fabricate thick PZT films, with thickness varied from 5 to 100 µm [3-8]. On the other hand, a low process temperature for the PZT thick films is required to ensure compatibility with the Si micro-machining process. In the case of thick films prepared by the powder source technique, such as screen printing [1, 9], the usual firing temperature is more than 800 oC, and the density of the thick films are not so high because of imperfect sintering. Compared with a screen printing process, thin film preparation processes using chemical solutions, like sol-gel, have the advantage of a low firing temperature and dense microstructure despite the low film deposition rate. Therefore, a chemical solution deposition (CSD) process is considered to be an attractive C10.5.1
way to ensure compatibility with the Si micro-machining process and to fabricate MEMS devices. On the other hand, it is hard to measure small film displacements to evaluate the piezoelectric properties. We measured PZT thin film displa
Data Loading...
